Deducted in a Flash
by Captain Spunker
Summary: When a British citizen and potential metahuman goes missing after the Eiling/Firestorm incident, Barry discovers that Scotland Yard is sending over a "consulting detective" named Sherlock Holmes to investigate the disappearance. Problem is, Sherlock is incredibly observant- and doesn't believe in superpowers. What's the Flash to do to keep the Brit from finding out his secret?


**Hello all! Captain Spunker here with a new story! A couple months ago I got into CW's _The Flash_ TV show, but when I went looking for a _Flash/Sherlock_ crossover, I couldn't find one (although I admit, I didn't dig very deep). It seems so obvious to me to put the two together, though. I mean, a super CSI and a consulting detective? How awesome is that?! Naturally, I had to fill in what I perceived as a gap in the market, and thus, _Deducted in a Flash_ was born.**

 **By the way, I just uploaded a new chapter to Silver Wizard, so go check that story out if you're interested. Also, I might edit this chapter so that it's longer. Sorry it's a bit short!**

 **And, as sad as this makes me, I'm taking _The Twelfth Dancing Prince_ down. It doesn't seem to have gotten any attention, so if you want to read that story and show it some love, I'm giving you guys a week until I pull its plug. Maybe I shouldn't have put it in the crossover section...**

* * *

"Okay, _what?!_ "

Joe looked up at him. "What 'what?'"

"You're telling me that Sherlock Holmes is a _real_ person _and_ he's coming over to Central City?"

"I'n't that what I just said?"

Barry raised his eyebrows. "Sherlock Holmes is real and he's coming to Central _why_?"

"He's here for a missing persons case. Apparently a British citizen who's been living here went off the radar just recently and they haven't been successful in finding the person, so they're calling in the expert."

"They who? Scotland Yard?"

Joe nodded. "Yep. We've been cooperating with them ever since we got wind of the disappearance, but we haven't exactly found anything yet. Either the person was kidnapped and his captor is good at erasing tracks, or the person himself is good at erasing tracks."

"And they're sending a civilian over? Couldn't they just send one of their own? Or are they swamped?"

Joe rubbed his face. "The detective we've been communicating with told me, and I kid you not, 'He may be an arsehole and slightly insane, but he's better than all of Scotland Yard combined.' He also told us to make sure he doesn't get hurt— which I'm guessing means Lestrade kind of thinks of Holmes like a son."

"… _Slightly_ insane, huh?"

Joe shrugged.

Barry sighed. "Lovely. And since I'm the CSI here, I might end up working with him." His phone blared, and he answered it. "Got it. I'm on my way. Sorry Joe, gotta dash!" _Voosh!_

"Wait! Barry!"

"Huh?" The young man peeked back in the lab.

"If this guy is as good as they say he is, you're gonna have a hard time keeping him from finding out who the Flash is. You need to be extra, extra careful, got it? Watch everything you say or do at all times."

Barry frowned. "Yeah. Okay. I'll just have to figure out how to out-think him then. Thanks!"

And with that, he was out on the street running to STAR Labs.

* * *

That night, Barry read over the case file Joe had given him on the British missing person. _Lawrence Owens. 21 years of age. Moved to Central City over a year ago. Wait, over a year ago?_ He bit his lip and fingered a sticky note stuck at the bottom of the page, decorated with Joe's handwriting. _"Was here for particle accelerator explosion. Metahuman?"_ He sucked in a breath. If the British government found out one of their citizens had been potentially harmed on American soil… but the two countries had an okay relationship, right? _And the explosion was an accident,_ he reminded himself. _I'm sure they'll understand._

 _But if Owens was a rogue metahuman—_ he shuddered. He already had enough on his plate what with the Eiling/Firestorm incident still fresh in his memory. Barry sighed and shook his head, speed-reading the rest of the file. Then he stood and went to his bedroom, dropping the file off in Joe's room.

First things first: figure out every angle that Holmes could use to divulge his scarlet alter-ego and come up with every last possible contingency plan so that the detective wouldn't suspect a single thing.

* * *

"Sherlock Holmes, world's only consulting detective. And this is my friend Dr. John Watson."

Barry fought back a snort at the pretentious title as the pasty brunette introduced himself and his short blond partner to the CCPD. " _Only,'' huh? You have proof?_

"You'll be working with our CSI here," Captain Singh ushered Barry over. "He doesn't look like much, but he's the best we've got."

"Barry Allen," the speedster introduced himself, shaking the taller Brit's hand, "nice to meet you. Call me Barry."

"I see." Holmes proceeded to rattle off insults about Barry's less-than-appealing attributes, like the fact that he was habitually late, had a crush on his foster father's daughter, and was a terrible liar, while Dr. Watson glared at his friend for his lack of tact. Barry stared at the brunette.

"W-Where'd you learn all that?"

Holmes smirked. "I deduced it. Obviously."

The CSI grinned. "Wow. Joe was right. You _are_ an expert. …And a jerk. But still an expert."

" _Sherlock_. Apologize," Dr. Watson grumbled. Barry laughed and shook his hand. "Sorry about him, he does that to everyone he meets. You can call me John, by the way."

"Sure thing."

As they went upstairs to the lab, John added, "Don't expect him to remember your first name, he's most likely deleted it as unimportant. And he'll probably be hardest on you because we're used to dealing with a… rather narrow-minded and incompetent forensic back home. Sherlock's kind of rivals with him."

"Great." Barry groaned. "He's probably not going to let me do my job, is he."

"Unless you prove to him otherwise, pretty much."

Inside the lab, Joe handed Owen's file to Sherlock, who flipped through it. "Metahuman? Rather odd term, don't you think?"

Joe cleared his throat. "Do either of you know about the particle accelerator explosion that occurred about a year ago here in Central City at STAR Labs?"

"Of course we do, I read everything I could get my hands on about it!" Holmes sniffed, affronted. "Harrison Wells had quite some fascinating theories so it was only natural that I learn about his latest endeavor. That doesn't explain the term 'metahuman,' however."

"When the particle accelerator blew, it released dark matter into Central City that killed some people and gave others fantastic abilities. We've been calling these people metahumans because of their powers."

"Powers?" Holmes snickered. When nobody joined him, he stopped. "You're serious."

"These people can be very dangerous, Mr. Holmes, they've been using their powers for crime— well, most of them, anyway. They can do things like control the weather, turn into steel or poison gas, or clone themselves into an army. If Owens turns out to be a metahuman, we might have to let the Flash deal with him."

"The… _Flash?_ "

"You mean the superhero?" John queried. "From the comics?"

Joe grunted. "Didn't know there were comics. But yeah, he's kind of a big deal here. Helps us here at CCPD out, even."

Holmes raised his eyebrows. "I didn't take you to be into fairy tales, Detective West."

 _Oh no, you didn't._

"Trust me, Mr. Holmes, when I say that most of us here in the precinct, including myself and Captain Singh, as well as plenty of people in the city, have witnessed the Flash and the other metahumans at work," Joe growled. "You need proof? I can give it to you."

"I'm surrounded by idiots," Holmes muttered. "These metahumans are clearly good at elaborate illusions if that many people believe in their powers."

"Okay, he's a bigger jerk than I thought," Barry confided to John. "Can I punch him?"

"That's my job, but I'd be happy to let you take a swing at him after I'm done."

Barry couldn't help himself. "Aye aye, cap."

"Cap?" John looked at him, confused. Holmes frowned at the CSI.

"You know, short for 'captain?'" The others stared at him. "Oh, come on! His right arm is a little slower than his left, which is indicative of a shoulder injury, probably from a bullet. He's got a military-style haircut and tan lines at the wrists, and that 'at attention' posture just screams 'soldier.' He's also got a subtle commanding presence, so he's clearly been in charge of at least a regiment. So I went with 'captain' 'cause it suited him. Oh, and you're a doctor too, right?" he addressed John. "Army doctor! That's it! See?"

Holmes furrowed his brow. "How—"

"I deduced it." Barry smirked. "Obviously."

John laughed as the brunette Brit sat there, stunned. "Not bad at all, Barry! You just might give Sherlock a run for his money!"

The youthful speedster grinned as Holmes narrowed his glasz eyes. _Well, now h_ _e can't take me for granted. Game on!_

* * *

"What the hell were you thinking?!"

Barry crossed his arms. "Come on, Joe, he deserved it! Didn't you get even the tiniest bit of satisfaction when I shut him up?"

Joe gripped the wheel harder, knuckles going angry white. "You've put yourself on his radar, Bear! How do you expect to keep him from finding out that you're the Flash if he's taken an interest in you?!"

"It's not like he believes the Flash exists anyway," Barry retorted. "He'll probably brush it off as being an 'elaborate illusion.'"

"Barry, the more time you spend with him, the more he's gonna pick up on the unusual things! You saw what he figured out about you with what, all of two seconds? You basically can't be the Flash at all until he leaves!"

"Joe, I can't do that! You know I can't, this city— the metahumans— they need the Flash! And if Owens turns out to be a metahuman, a criminal one, the Flash is the only one who can take him down!"

As they pulled up to STAR Labs, Joe sighed. "Look, Bear, just… try not to give him a reason to suspect you, okay?"

"I'll do my best, Joe, I promise. Caitlyn, Cisco, and Dr. Wells are helping me come up with every last outlet that Mr. Holmes could use to figure out I'm the Flash." Barry got out of the car. "Like I said, I'll use the utmost care in everything I say and do, all right?"

The detective gazed at him, then nodded. "That's probably the best we can hope for."


End file.
